Apparatus for the manufacture of a plastic pipe having transverse profile features

An apparatus for the molding from a plastic tube (23a), a plastic pipe having transverse profile features, in particular ribs (22), comprising

• a machine bed (1) defining a horizontal plane,
• a first guide device (13) and a second guide device (14) arranged parallel to each other and to the horizontal plane and to a direction (4) of production, at least one of said first and said second guide device being displaceably guided in a direction (28) of displacement, which direction (28) of displacement is perpendicular to said direction (4) of production and parallel to the horizontal plane,
• pressure devices connected to said at least one of said first and second guide device and acting upon said at least one of said first and second guide device in the direction (28) of displacement,
• a molding path (9) defined between said first and said second guide device (13, 14), said molding path (9) having a first end and a second end,
• half shells (2, 2') arranged on the machine bed (1) in a first continuous series and a second continuous series, said second continuous series being arranged in mirror symmetry to said first continuous series with respect to the molding path (9) and the half shells (2, 2') arranged in the molding path (9) in the form of pairs, each pair consisting of one half shell (2) of said first continuous series and one half shell (2') of said second continuous series and several of such pairs arranged one behind another in said molding path (9) between said first and said second guide device (13, 14) and defining a molding chamber (24) for molding the plastic pipe and said half shells of one pair of half shells being pressed together by said guide devices,
• a drive arranged adjacent to said first end of said molding path (9) being in driving engagement with one pair of half shells (2, 2') to push said half shells (2, 2') from said first end to said second end of said molding path (9),
• means for guiding the half shells (2, 2') outside of said molding path (9) from said second end to said first end of the molding path (9), wherein the pressure devices are hydraulically actuatable piston-cylinder drives (31, 31a, 31b), connected by hydraulic lines (37, 38, 37a, 37b, 38a) to a control valve (39), and
• wherein control means are provided which upon overpressure in the molding chamber (24) trigger the control valve (39) to move said at least one of said guide devices (14) in the direction (28) of the displacement away from the molding path (9).